1. Field of Invention
The subject invention relates to a seat track assembly for a seat assembly of an automotive vehicle. More particularly, the subject invention relates to a seat track assembly having a locking mechanism with a plurality of shear plates movable between a locked position wherein at least one of the plates interlocks upper and lower tracks of the seat track assembly and an unlocked position disengaged from the tracks to allow sliding movement therebetween.
2. Description of the Related Art
Locking mechanism are commonly known in the art for interlocking the upper track and lower track of a manual seat track assembly to prevent relative fore and aft sliding movement therebetween. One type of locking mechanism known in the art utilizes a locking plate operatively secured to the upper track and having a projecting finger for aligning with and engaging an aperture within the lower track to interlock the upper and lower tracks. Examples of these type of locking mechanisms are disclosed in U.S. Pat. Nos. 4,189,957; 4,635,890 and 4,961,559.
However, these locking mechanism are limited in their range of engagement caused by the necessary alignment of the projecting finger with the aperture. That is, the occupant of a seat assembly must properly position the upper track along the lower track until the projecting finger is aligned with the aperture to engage therewith and interlock the upper and lower tracks. This alignment necessity limits the range of adjustable travel of the seat assembly by the seat tracks as well as the range of engagement of the locking mechanism. Further, if the projecting finger is not properly aligned with the aperture, a possibility exists that the upper and lower tracks will not interlock and prevent incidental fore and aft movement of the seat assembly.
Therefore, it is desirable to provide a seat track assembly having a locking mechanism which provides for infinite engagement between the upper and lower track to interlock the tracks and prevent fore and aft movement of the seat assembly.